Recently, various geriatric diseases have been increased with coming of an era of the advanced age society and now become to be a serious social problem. A typical example of these diseases is osteoporosis which is often observed in persons of advanced age, in particular, postmenopausal women. In bones, salts of calcium as well as phosphorus, magnesium and sodium are present in large amounts. In a recent national nutritional investigation, insufficient intake of calcium was pointed out, and this is assumed to be one of reasons for the increase of osteoporosis. From such a background, a number of calcium-enriched foods has been developed and is now commercially available. Further, an effect of the calcium replenishment on the therapy or the suppression of symptom of osteoporosis has been extensively studied.
However, there are not a few reports in which a mere replenishment of calcium is confirmed to be ineffective to the treatment or the suppression of symptom. The reason therefor is considered that, in persons of advanced age, it is highly possible that an absorption of calcium decreases, and that not only calcium but also minerals which constitute the bone are required to be adsorbed in a well-balanced manner.
The present inventors have already observed that indigestible oligosaccharides promote an absorption of minerals such as calcium, magnesium, phosphorus and iron, and, by taking an advantage of this activity, developed a magnesium replenishment (Japanese Patent Application No. Hei-5-191591) and an improving material for iron deficiency anemia (Japanese Patent Application No. Hei-5-313948) and filed patent applications therefor. Also, with respect to calcium, the present inventors observed that the indigestible oligosaccharides increase an absorption of calcium and further increase a calcium content in bones in the test using rats at a growth stage (Nippon Eiyo Shokuryo Gakkai-shi, 1993, Vol. 46, No. 2, pp 123-129), but their clinical significance was not apparent.